package exercise4;

public class Arrays {
    public static void main(String[] args) {
        System.out.println(f(10));
    }

    public static int f(int n){
        if (n == 0){
            return 1;
        }
        else {
            if (n == 1){
                return 4;
            }
            else {
                return 2 * f(n - 1) + f(n - 2);
            }
        }
    }
}
